Similar - maybe I used a bad word but I ment - similar in meaning, sth like synonyms... Or words I can use instead of them. The problem is - I don't know the diffrences between words I've written before

OlgaD wrote:Similar - maybe I used a bad word but I ment - similar in meaning, sth like synonyms... Or words I can use instead of them. The problem is - I don't know the diffrences between words I've written before

Ok, OlgaD.
When it comes to daily conversation, the usuful words are different from the ones you find in textbooks. Right?
So, if you want to know the words you want to use, there are some approprite words in the context. If you just want to study grammar and words definition, all what you need is a thick grammar book and a big dictionary.

So, instead of asking for the explanation of the words, I recommend you to make a couple of sentences in Japanese with words you know. Many forum members would help you to make your sentence better.
How does it sound to you?

According to my question...
I've heard that 男子 (and also 女子) are used commonly ONLY when referring to school or university (for ex. boy's/girl's university) and for ex. to pupils in a class (when I say IN MY CLASS THERE ARE 20 GIRLS should I use 女子?). Am I right?
I've also heard that when a child is born and we ask is it a boy a girl, we use 男の子 and 女の子?
So...
Is 男子 more polite form of 男の子 (or maybe 男の子 is more polite?) or are they just used in different situations? For ex.女子学生 or女子校 but 私のむすめはきれいな女の子です. Am I right?
I've also heard that 女 is less polite than 女の人. Is it the only difference?

Hi Olga, your understnding is almost correct.
However, there are tons of exceptions in reality.

OlgaD wrote:
I've heard that 男子 (and also 女子) are used commonly ONLY when referring to school or university (for ex. boy's/girl's university) and for ex. to pupils in a class (when I say IN MY CLASS THERE ARE 20 GIRLS should I use 女子?). Am I right?

That's common. But not "only". We use both in many situations.
Generally, クラスの女子 sounds more proper than クラスの女の子.
Calling 女の子s 女子 in schools is a kind of official way or "commonly used" way.
But there are many situations we use 女子 instead of 女の子, such as 肉食女子 or 女子力.

I've also heard that when a child is born and we ask is it a boy a girl, we use 男の子 and 女の子?

Correct.

So...
Is 男子 more polite form of 男の子 (or maybe 男の子 is more polite?) or are they just used in different situations?

I wouldn't use the word "polite". In many official papers at schools, 男子 would be used. But if you said "おたくの男子は" to his parents, it could sound kind of rude.

The most easiest explanation would be "男子／女子 are school terms that can be used even outside of the school".

For ex.女子学生 or女子校 but 私のむすめはきれいな女の子です. Am I right?

Correct.

I've also heard that 女 is less polite than 女の人. Is it the only difference?